在线检测数控机床主轴径向误差

数控机床加工工件时，在切削力的作用下，实时测量机床主轴的径向运动误差，并采用小波变换算法去除加工时存在的噪声。同时，从谐波抑制特性和总体频域特性两个方面讨论了测量系统频域特征。     

机床主轴径向误差运动在线检测与信号处理

在机床加工工件时,实时测量机床主轴的径向运动误差。测量对象是在该机床上加工的圆柱形工件,而不是通常所使用的标准棒。采用误差分离技术将工件的形状误差从所测信号中分离出来,实现在线测量主轴的径向误差运动。并采用基于自适应阈值的小波包算法去除加工时存在的噪声。同时,从谐波抑制特性和总体频域特性两个方面分析了测量系统频域特征。     

工件轮廓曲线磨削加工精度的原位测量与评定方法研究

为了解决曲线磨削中工件轮廓加工精度的在位评定问题,提出了一种基于机器视觉的工件轮廓曲线磨削加工精度原位测量和评定方法。应用这一方法,通过视觉测量系统和亚像素边缘提取算法,得到工件的实际轮廓边缘点。通过轮廓匹配算法来确认工件实际轮廓与理论轮廓的最优匹配位置,进而计算轮廓偏差,进行加工精度评定。分别进行了标定板试验和工件试验,表明所提出的评定方法精度可达0.6像素,能有效保证工件轮廓在位检测的精度和效率。     

多面加工零件的工件坐标系的换算法

利用加工中心加工多面零件时,其各加工面工件坐标系x、y、z的确定不必一一去测量,可只由某一个加工面的工件坐标并结合机床本身x、y、z的行程换算出来。该“换算法”可减少测量误差,具有精度高、一致性     

干切削的刀具和切削条件选择（下）

刀具确定以后，还应选择合适的切削用量和其他参数，根据具体加工，来确定出干切削的适用性。为此有人用涂层硬质合金(P15)车刀，对中碳钢进行精切加工。工件硬度55～59HRC，直径Ф98-Ф70mm，长度250mm。机床为精密的CNC车床，主电机功率22kw。车削时若使用切削液则为浓度6％合成油的水溶液，流量为4．2L／min。加工时刀具用光学显微镜测量其磨损，刀具的磨钝标准为VB=0．3mm。工件表面粗糙度用轻便式粗糙度仪测量，主电机的电流用霍尔传感器测量。     

基于八叉树的复杂曲面测量路径规划

针对异形天线罩复杂曲面的测量加工一体化加工方法中,存在测量复杂曲面时测杆与工件易发生干涉,使得数控编程困难的问题,提出了一种复杂曲面测量路径规划方法。该方法将机床测量系统离散为点云数据,通过点云的空间坐标变换来模拟数控测量时测杆与工件的位置关系,同时引入八叉树算法为点云增加拓扑关系,并检测测杆点云与工件点云之间是否发生干涉。最终将无干涉测量状态下的测量系统信息输出为G代码,通过Vericut软件进行轨迹仿真。文中对8 504个测量点进行测量路径规划,结果表明,测量路径均可以避开干涉位置进行有效地测量。该碰撞检测算法可以在满足测量要求的前提下准确地实现复杂曲面的测量路径规划,为复杂曲面的测量方法提供理论指导。     

三维工件激光切边的自动编程

给出了进行三维工件激光切边时，自动寻找工件边界的激光加工轨迹的算法。用直线段逼近曲线，用小三角平面逼近曲面计算法线，根据激光头与法线的关系计算出激光加工时姿态，完成三维激光切边。     

检测自由曲面时精确定位方法的研究

针对用三坐标测量机对自由曲面轮廓进行测量时由于工件找正时的定位误差引起的测量误差，提出了一种将实际测量数据点与工件的ＣＡＤ模型理论数据点优化匹配的算法。使用该算法可有效地消除最终测量结果中由于定位误差引起的系统误差     

表面粗糙度测量的注意事项

在技术测量中粗糙度的测量有４种，粗糙度样板比较、光切法显微镜测量、干显微镜测量、电动轮廓仪测量。下面对这４种测量法分别进行分析。比较法测量在技术测量中，用粗糙度样板对比最简单，利用各种机床加工后的样板通过人的视觉或触觉与工件相比较，可得出加工出来的零件表面粗糙度。对比时，所用的粗糙度样板的材料、形状和加工方法应尽可能与被测表面相同，这样可以提高判断准确性。光切法显微镜测量测量仪器用９J显微镜。在测量过程中，采用工件为车床加工一轴套的一半作为工件，为了测量方便，采用微观不平度１０点高度RZ较大的工…     

以滚压代磨削的铸铁套加工

在批量加工图1所示的铸铁套9时，为了满足铸铁套外圆表面粗糙度Ra0．8μa的要求，过去通常采用磨削工艺，但加工效率低。为了提高生产效率，我们设计制作了一种滚压工具，在车床上对工件外圆进行滚压加工，取得了十分满意的效果。     

机床主轴运动误差的在线高精度测量

常规时域三点法误差分离技术可以在线测量机床主轴的回转运动误差，但初值问题是影响测量精确程度的主要因素。为此，作者提出了先使用频域法确定表面形状误差的误差初值，然后用时域三点法测量数控机床主轴运动误差的新方法。该方法有效地解决了限制时域三点法应用的初值问题，实验证实了该方法的正确性。     

Modeling, measurement, and evaluation of spindle radial errors in a miniaturized machine tool

Miniaturized machine tools have been established as a promising technology for machining the miniature components in wider range of materials. Spindle of a miniaturized machine tool needs to provide extremely high rotational speed, while maintaining the accuracy. In this work, a capacitive sensor-based measurement technique is followed for assessing radial errors of a miniaturized machine tool spindle. Accuracy of spindle error measurement is affected by inherent error sources such as sensor offset, thermal drift of spindle, centering error, and form error of the target surface installed in the spindle. In the present work, a model-based curve-fitting method is proposed for accurate interpretation and analysis of spindle error measurement data in time domain. Experimental results of the proposed method are presented and compared with the commonly followed discrete Fourier transform-based frequency domain-filtering method. Proposed method provides higher resolution for the estimation of fundamental frequency of spindle error data. Synchronous and asynchronous radial error values are evaluated in accordance with ANSI/ASME B89.3.4M [9] standard at various spindle speeds and number of spindle revolutions. It is found that the spindle speed and number of spindle revolutions does not have much influence on synchronous radial error of the spindle. On the other hand, asynchronous radial error motion exhibits a significant speed-dependant behavior with respect to the number of spindle revolutions.     

五点法测量机床主轴轴向及倾角的运动误差

提出了测量机床主轴的轴向及倾角运动误差的端面五点法。在轴端面绕轴心的某一圆周上,垂直于轴端面,按通过误差分析优化确定的位置,布置五个测头,在主轴回转一圈中同时测得主轴的轴向及倾角运动误差以及端面基准的形状误差,并将测头的读数及定位误差的影响降至最低程度。本方法可用于机床主轴回转精度的实时测量,试验表明其测量精度可达亚微米级。     

机床主轴运动误差的在线高精度测量

初值问题是影响时域三点法测量机床主轴回转运动误差的主要因素。为此 ,提出先用频域法确定圆度误差的误差初值 ,然后用时域三点法测量数控机床主轴运动误差的新方法并实证该方法的正确     

A new method for characterizing axis of rotation radial error motion: Part 1. Two-dimensional radial error motion theory

In the current standards of spindle metrology, the fundamental component of radial probe measurement is considered radial throw (eccentricity) of the installed test artifact and the fundamental radial error motion is treated as non-existent. The goals of this paper are: (1) to make evident the fact that fundamental radial error motion can actually exist; (2) to present a new two-dimensional (2D) method to analyze spindle radial error motion measurement; (3) to discuss the limitations of current spindle motion analysis methods. In the 2D framework, the radial error motion is an application-independent geometric property and thus separate from the consequence of radial error motion in spindle applications. The 2D method can not only determine the axis of rotation radial error motion, but also the consequence of error motion in all classes of spindle applications, including a new class of spindle applications with two radial sensitive directions. In comparison, the radial error motion values specified in current standards give the consequence of radial error motion in two classes of spindle applications, but do not represent radial error motion itself. The new method is presented in two parts. Part 1 focuses on the theory and illustration of the 2D method. Part 2 presents the experimental results of a ball bearing spindle and an aerostatic bearing spindle.     

A new method for characterizing axis of rotation radial error motion: Part 2. Experimental results

In the current standards of spindle metrology, the fundamental component of radial probe measurement is considered radial throw (eccentricity) of the installed test artifact and the fundamental radial error motion is treated. The goals of this paper are: (1) to make evident the fact that fundamental radial error motion can actually exist; (2) to present a new two-dimensional (2D) method to analyze spindle radial error motion measurement; (3) to discuss the limitations of current spindle motion analysis methods. In the 2D framework, the radial error motion is an application-independent geometric property and thus separate from the consequence of radial error motion in spindle applications. The 2D method can not only determine the axis of rotation radial error motion, but also the consequence of error motion in all classes of spindle applications, including a new class of spindle applications with two radial sensitive directions. In comparison, the radial error motion values specified in current standards give the consequence of radial error motion in two classes of spindle applications, but do not represent radial error motion itself. The new method is presented in two parts. Part 1 focuses on the theory and illustration of the 2D method. Part 2 presents the experimental results of a ball bearing spindle and an aerostatic bearing spindle.     

三点法中测头角位置的精密测量方法

研究了三点法圆度及轴系误差测量中测头角位置的精密测量方法。设计了能直接测量非接触电容传感器测头实测状态下的角位置的测角系统,提出了克服测头角位置测量误差及三个测头灵敏度标定误差影响的校正方法。实验表明：采用本文提出的“多刻线”法测角精度优于1′,测头角位置测量误差及三个测头灵敏度标定误差对测量精度的影响可降致最小。     

一种圆柱度测量基准的误差分离方法

通过对主轴回转误差运动的分析，结合三点法圆度误差分离技术，提出了一种完全分离圆柱度测量基准误差的分离方法，即利用主轴回转轴线平均线、测量传感器及直行导轨之间的空间位置关系，建立相应的坐标系，在分离出被测截面圆度误差、最小二乘圆心初始坐标的基础上，完整地分离出影响圆柱度精密测量的径向回转运动误差和导轨的直行运动误差。该技术不仅可以消除测量基准误差对圆柱度测量精度的影响，还可以实现主轴回转误差、导轨直线度以及导轨对主轴平行度误差的精密测量，对高精度误差补偿加工和机床的精度检验也具有重要意义。     

A sub-nanometre spindle error motion separation technique

This work designs and validates a spindle error motion separation technique having a sub-nanometre measurement uncertainty. This technique overcomes typical measurement error sources arising from sensor, indexing or the repositioning of the artifact. We compare and assess various known reversal and multiprobe techniques by means of a novel error analysis method. From this, we develop an improved implementation of the multiprobe technique, which by-passes accurate indexing of the artifact and sensor(s) during testing, as well as unequal sensor sensitivities, in case multiple sensors are used. This is achieved by measuring the error motion consecutively under three different orientations by rotating the stator of the spindle utilising a high-precision indexing table. These modifications result in a measurement uncertainty that is four times smaller than the conventional multiprobe technique. Furthermore, the suppression of the low-order harmonics is reduced by an optimisation of measurement angles. Finally, several experimental tests are performed to quantify the measurement uncertainty and the influence of the measurement angles on the error separation. Repeatability tests on the radial error motion of an aerostatic rotary table show a measurement uncertainty of 0.455 nm.